1. Field of the Invention
This invention relates to a rolling mill of the type having two drive rolls between which at least one rolling path is provided for the passage of the material to be rolled, with each drive roll being supported by at least one backing roll.
2. Description of the Prior Art
Rolling mills (or roll stands) of the type contemplated herein are particularly suitable for rolling metal foils and webs of similar material. One example of a rolling mill which accomplishes the rolling objective with less weight and complexity than previously known mills is described in commonly assigned U.S. patent application Ser. No. 655,767, filed Feb. 6, 1976. In this mill, backing rolls are provided for the working rolls, each backing roll being provided with a rotatable barrel (or roll shell) which is hydrostatically supported on a stationary member in a manner somewhat similar to the technique utilized for controlled deflection rolls. The deflection due to the load is taken solely by the backing roll support members with the result that the roll barrels are practically free from deflection, sag or flexure. The great number of backing rolls which otherwise may be required are thus avoided, while those backing rolls actually provided need not be dimensioned for strength, but rather they are dimensioned to undergo a minimum of deflection.
In such rolling mills, the web of material to be rolled generally passes directly between the two drive rolls which are connected to a drive mechanism, and the drive rolls thus roll the material directly. Consequently, the drive rolls must have relatively large diameters in order to enable them to withstand the necessary torque requirements for rolling. Thus, it will be seen that relatively large forces and torques are generated and transmitted during the material rolling process. We have invented a rolling mill in which the rolling forces and the torques of the drive rolls are further reduced, thereby providing an even further simplification of the rolling mill. Further, it will be seen that if the dimensions of our inventive rolling mill components remain unchanged from the earlier developments, our present rolling mill will provide an even greater reliability and accuracy in the rolling operation.